Synthesis, characterization, and thermal decomposition kinetics of copper hydroxide sulfate (Cu4(SO4)(OH)6) synthesized by chemical precipitation method

In this study, copper hydroxide sulfate (Cu4(OH)6SO4) was synthesized by chemical precipitation using CuSO4 as the precursor material and the first time borax as basic precipitating agent. The synthesized samples were characterized using XRD, FTIR, and SEM. The decomposition kinetics of Cu4(OH)6SO4 were examined by the thermoanalytical procedures. It was obtained from TG-DTG data that Cu4(OH)6SO4 has two-region decomposition at elevated temperatures. Kinetic parameters of these regions were calculated by using both the model-fitting and model-free methods. In the decomposition of copper hydroxy sulfate, the mean activation energy for first region was calculated as 90.88 kJ mol−1 from KAS method and 91.47 kJ mol−1 from FWO method. The mean activation energy for the second region was 207.20 kJ mol−1 from KAS and 213.34 kJ mol−1 from FWO. The activation energies for first and second regions were obtained from Ortega method as 56.3 and 198.3 kJ mol−1, respectively. © 2020 Curtin University and John Wiley & Sons, Ltd.